The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, the semiconductor industry utilized various methods to form semiconductor devices for controlling high voltage systems. One example of such a high voltage system was a power supply controller that operated from input voltages having high voltage values. One problem with these prior semiconductor devices was an inability to sense the value of the high voltage in a continuous manner. Typically, external circuits were utilized to provide voltages that were representative of the value of the high voltage. For example, a controller may operate from an input voltage of several hundred volts and the value of this voltage may change with respect to time. In order to provide efficient operation, the controller may need to sense the value of this voltage as it changes during the operation of the controller. The inability to produce devices on a semiconductor chip that could be used to sense the value of the high voltage resulted in using the external components which increased the cost of the system.
Accordingly, it is desirable to have a semiconductor device that can sense the value of a high voltage signal.
For simplicity and clarity of illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain N-channel or P-Channel devices, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. For clarity of the drawings, doped regions of device structures are illustrated as having generally straight line edges and precise angular corners. However, those skilled in the art understand that due to the diffusion and activation of dopants the edges of doped regions are generally not straight lines and the corners are not precise angles. The use of the word approximately or substantially means that a value of an element has a parameter that is expected to be very close to a stated value or position. However, as is well known in the art there are always minor variances that prevent the values or positions from being exactly as stated. It is well established in the art that variances of up to at least ten per cent (10%) (and up to twenty per cent (20%) for semiconductor doping concentrations) are reasonable variances from the ideal goal of exactly as described.